Thank you. Any project that closes a real issue without solving it is a joke to me.
No real issues have been closed cursor pagination has been working for years. This issue clear says "frederikhors closed this as completed on Mar 3, 2020" as in closed by the person who opened it.
Unfortunately, there are two closed out issues, seemingly with no resolution, that seem to indicate cursor-based pagination doesn't work (with Relay) and perhaps correctly (at all).
[0] https://github.com/dosco/graphjin/issues/44
[1] https://github.com/dosco/graphjin/issues/47